The most common and most likely answer to this crossword clue is the 6 letter word FIRING
I've seen this crossword clue in The Guardian
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Buddy explains!

The straight part
We know that "Exciting" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case exciting = firing.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does FIRING mean?
FIRING verb- To set (something, often a building) on fire.
- To heat as with fire, but without setting on fire, as ceramic, metal objects, etc.
- To drive away by setting a fire.
- To terminate the employment contract of (an employee), especially for cause (such as misconduct or poor performance).
- To shoot (a gun or analogous device).
- To shoot a gun, cannon, or similar weapon.
- To shoot; to attempt to score a goal.
- To cause an action potential in a cell.
- To forcibly direct (something).
- (computer sciences, software engineering) To initiate an event (by means of an event handler).
- To inflame; to irritate, as the passions.
- To animate; to give life or spirit to.
- To feed or serve the fire of.
- To light up as if by fire; to illuminate.
- To cauterize.
- To catch fire; to be kindled.
- To be irritated or inflamed with passion.
- The process of applying heat or fire, especially to clay etc to produce pottery.
- The fuel for a fire.
- The act of adding fuel to a fire.
- The discharge of a gun or other weapon.
- The dismissal of someone from a job.
- Cauterization.